I’m thrown terminate called after throwing an instance of ‘EDDY::KMatrixException’ what():
This error is entirely internal to eddy; MRtrix3’s dwipreproc script is simply passing this error message from the underlying command to the user. So I can really only suggest going into the temporary directory that was preserved by the script, and attempting to invoke eddy directly. You can also manually inspect all of the files that are being provided as input to eddy, and ensure that they are sensible according to the usage of that command. If that seems to be the case, then your question should instead be posed on the FSL mailing list, as it is independent of MRtrix3.
Note: If you say to FSL that you’ve encountered this issue when trying to run an MRtrix3 script, they won’t help you. You must validate yourself that the issue is indeed with eddy, and not with MRtrix3’s wrapping thereof, and then report it as such. Alternatively, if your investigation shows that dwipreproc is providing inappropriate data to eddy, then this is precisely the information that needs to be provided here in order for the issue to be fixed within MRtrix3.
dwipreproc: Output of failed command: dwipreproc: Changing back to original directory (/home/wpy/Desktop/FBA/p01)
In your case @PinyiWang, eddy appears to not be providing any error message to the terminal whatsoever. Nevertheless, even in this case, the same instructions as given above to @Sabina_R apply to your case also.